<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        canvas {
            border: 1px solid black;
            margin-top: 10px;
        }
    </style>
    <script type="module" src="入口.js"></script>
</head>
<body>
    <button class="圆形">圆形</button>
    <button class="正方形">正方形</button>
    <button class="三角形">三角形</button>
</body>
</html>